The project is attempting to better characterize the pathophysiology of chronic orofacial pain through 1) evaluating the relationship between sleep disturbances and temporomandibular disorders (TMD) which are thought to result in nocturnal muscle hyperactivity leading to pain the muscles of mastication especially upon awakening. The study involves a double-blind crossover design in which 20 subjects receive either triazolam, a benzodiazepine hypnotic, or placebo over the course of five days with concurrent monitoring of pain and sleep architecture. Following a washout period of three days, subjects receive the alternative treatment and are monitored similarly. Documentation of an improvement in the quality and quantity of sleep by polysomnography and a parallel change in pain in the temporomandibular region is interpreted as evidence of a relationship between alterations in sleep architecture, sleep quality, and pain in the muscles of mastication. New studies will be assessing alternative treatment strategies for the management of temporomandibular disorders and sleep disturbances to include cognitive behavior therapy combined with tricyclic anti-depressants. 2) Investigating arthrocentesis of the temporomandibular joint (TMJ) as a possible therapeutic modality and as a randomized double-blind design to administer a saline wash or an anesthetic agent to the TMJ and then to assess the effect on pain and mandibular range of motion. The arthrocentesis of the temporomandibular joint (TMJ) as a possible therapeutic modality and as a means to collect fluid and cells from the TMD for later analyses. We use a randomized double-blind design to administer a saline wash or an anesthetic agent to the TMJ and then to assess the effect on pain and mandibular range of motion. The arthrocentesis is performed with a novel coaxial needle technique developed by the primary investigator. 3) Investigation of idiopathic jaw pain using single photon emission computed tomography (SPECT) to determine whether or not this pain might be the result of a neuralgia induced subacute osteonecrosis or osteomyelitis. Patients with a diagnosis of idiopathic jaw pain are being matched by age and gender with a cohort of normal controls without jaw pain. Both groups undergo a comprehensive dental examination followed by SPECT images of the head and neck. These are evaluated by a nuclear medicine physician who is unaware of the locations of the pain or whether the patient was a control subject without jaw pain. The relationship between regions of radioisotope uptake and the areas of reported pain and dental pathosis within the jaws is being evaluated in both groups.